JPH07317822A - Oil damper of high damp cylinder type - Google Patents

Abstract

PURPOSE:To effectively control vibrations of even a steel structure such as a bridge, which is vibrating in the axial direction always with a small amplitude, and also provide controllability for large amplitude vibrations to be generated in the event of a typhoon, earthquake, etc. CONSTITUTION:An oil damper with a high damping cylinder is equipped with a piston rod 23 having a front piston 22 and a rear piston 22 inserted in a front chamber and rear chamber partitioned by a center bulkhead 21 and an orifice 30 bored in the center bulkhead 21, and the gap between the two pistons 22, 22 is filled with a working oil 24. The arrangement further includes a servo valve 25 installed protrusively at the periphery of a cylinder 20 and, increasing or decreasing the section area of the orifice 30 in proportion to the size of the fed signal, an integrating amplifier 28 to which the output of an acceleration sensor 29 is fed, an A-V converter 27 to convert the output of the amplifier 28 into voltage, and a servo amplifier 26 which amplifies the output voltage signal of the A-V converter 27 and feeds the result to the servo valve 25.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high damping cylinder type oil damper applied to vibration control of steel structures such as bridges.

[0002]

2. Description of the Related Art For example, in suspension bridges and cable-stayed bridges, when a seismic isolation structure is adopted in the bridge axis direction, displacement in the bridge axis direction becomes large. It is inserted between the girder and the end pier. Conventionally, as shown in FIG. 7, an oil damper of this type has a pair of front and rear pistons 12, 12 in a cylinder 10 partitioned by a partition wall 11 having both ends closed by end plates and an orifice 15 at the center. It has a structure in which the piston rod 13 is inserted, and this is adjusted to a large amplitude during an earthquake or typhoon. However, in the oil damper having such a structure, although the relationship between the amplitude and the damping force has the characteristics shown in FIG. 8, it is effective for earthquakes and typhoons,
Because the orifice of the damper is large, the oil damper has almost no effect at the time of slight displacement due to traffic load or light wind.

[0003]

As described above, in the cable-stayed bridge, when the seismic isolation structure is adopted to reduce the load acting on the main tower at the time of an earthquake by lengthening the period in the bridge axis direction,
Since it is an oil damper that has an orifice hole that is adapted to large amplitude during an earthquake or typhoon, there is almost no damping effect when the amplitude is small due to traffic load or breeze during normal times. As a result, the cable-stayed bridge constantly vibrates in the axial direction of the bridge during normal times, making passengers anxious and uncomfortable while passing, and the sliding parts will wear out. is there.

The present invention has been proposed in view of the above circumstances, and is effective not only for large-amplitude vibrations but also for steel structures such as bridges that constantly vibrate in the axial direction with a small amplitude. It is an object of the present invention to provide a high-performance, high-damping cylinder type oil damper that suppresses vibration.

[0005]

Therefore, according to the invention of claim 1, both ends are closed by end plates, respectively, and the inside is symmetrically partitioned into a front chamber and a rear chamber by a partition wall at the center thereof. A cylindrical cylinder having central holes of the same diameter penetrating on the same center line of the both end plates and the partition wall and having an axial orifice eccentrically penetrating the partition wall, and the center of the both end plates. A circular rod that is inserted in the hole and the center hole of the partition wall in a fluid-tight and slidable manner is coaxially projected at the central positions of the front chamber and the rear chamber, respectively, and the outer circumferences are fluid-tight and slidable. A cylinder type oil damper comprising a piston rod having a front piston and a rear piston which are in sliding contact with an inner peripheral wall, respectively, and hydraulic oil sealed in a space between the pistons. Projecting from the central portion outer peripheral in proportion to the magnitude of the input signal, characterized in that comprises a servo valve to increase or decrease the cross-sectional area of the orifice.

According to a second aspect of the present invention, in the first aspect of the present invention, an integrating amplifier which is placed in front of the servo valve and which inputs the acceleration of the object output by the acceleration detector, and a speed signal output by the integrating amplifier are provided. A to convert the amplitude of to a voltage signal
A servo valve input signal circuit comprising a -V converter and a servo amplifier for amplifying an output voltage signal of the A-V converter and inputting the amplified voltage signal to the servo valve is provided.

[0007]

With this structure, as shown in FIG.
When the hydraulic oil 24 enclosed between the cylinder 20 and the pair of front and rear pistons 22, 22 passes through the orifice 30 provided in the partition wall 21 between the pistons 22, 22, depending on the magnitude of the vibration speed, By controlling the cross-sectional area of the orifice hole, the magnitude of the damping force is controlled. That is, when the vibration amplitude (vibration velocity) is small, the orifice hole is made small, and when the vibration amplitude is large, the orifice hole is enlarged accordingly. To control. As a result, as shown in FIG. 4, a large damping force can be continuously obtained regardless of the magnitude of the vibration amplitude.

[0008]

Embodiments of the present invention will now be described with reference to the drawings.
1 is an overall side view showing a first embodiment in which an oil damper according to the present invention is applied to a cable-stayed bridge, FIG. 2 is an enlarged view showing a II portion of FIG. 1, and FIG. 3 is a high damping oil damper of FIG. FIG. 4 is a longitudinal cross-sectional view showing the control system of the orifice, FIG. 4 is a damping characteristic view of the high damping oil damper according to FIG. 3, and FIG. 5 is an overall side view showing a second embodiment in which the present invention is applied to a viaduct. 6 is a plan view of FIG.

First, in the first embodiment, as shown in FIG. 1, in a cable-stayed bridge composed of a main tower 1, a main girder 2 and a cable 3, between the end piers 5 and the main girders 2, the main girder 2 As shown in, both ends of the oil damper 6 according to the present invention are attached via pin joints 7, 7, respectively. As shown in FIG. 3, the oil damper 6 is inserted into the front chamber and the rear chamber by penetrating through the central holes of the horizontal cylinders 20 whose both ends are closed and the center is partitioned by the partition wall 21 into the front chamber and the rear chamber. Each piston 22 has a pair of pistons, a front piston 22 and a rear piston 22, which are respectively inserted, and both ends thereof each have a piston rod 23 that penetrates through the front and rear end plates of the cylinder 20 and projects slightly to the outside. Is inserted in such a manner that the front chamber and the rear chamber partitioned by the partition wall 21 are internally partitioned. An axial orifice 30 is pierced through the partition wall 21 at an eccentric position, and a servo valve 25 is provided on the outer peripheral portion of the partition wall 21 so as to project outward in the radial direction. The cross-sectional area of 30 is controlled. Two
Reference numeral 9 is a servo-type piezoresistive acceleration accelerometer attached to one end of the main girder 2 shown in FIG. 2, 28 is an integrating amplifier as shown in FIG. 3, 27 is an AV converter, 2
6 is a servo amplifier.

In such a structure, as shown in FIGS. 2 and 3, the axial acceleration of the main girder 2 detected by the acceleration pickup 29 is converted and amplified into an axial velocity by the integrating amplifier 28, and A- The voltage is converted into a voltage corresponding to the input amplitude by the V converter 27, amplified by the servo amplifier 26, and then input to the servo valve 25. The servo valve 25 displaces its valve rod according to the magnitude of the output of the servo amplifier 26. To increase or decrease the cross-sectional area of the orifice 30. Although the servo valve 25 is used here as a means for changing the cross-sectional area of the orifice 30, a similar function can be achieved by combining a servo motor and a ball screw.

According to the structure of the first embodiment as described above, the relationship between the velocity amplitude of the main girder and the damping force is as shown in FIG. 4, so that the following effects can be obtained. (1) It is possible to reduce vibrations from a small amplitude during normal times such as traffic vibrations and breeze to a large amplitude during earthquakes and typhoons with the same oil damper, which leads to cost reduction. (2) Discomfort and anxiety caused by vibration of the bridge girder during normal traffic can be reduced. (3) It is possible to reduce vibrations in a small amplitude due to a traffic load, a breeze, and the like at normal times, and it is possible to prevent wear of sliding parts. (4) Since vibration can be reduced before amplification to a large amplitude, a large-capacity oil damper is unnecessary, resulting in compactness and cost reduction.

The second embodiment will be described with reference to the drawings. Since vibration and noise caused by high-speed running of a vehicle are large in an viaduct, recently, in order to damp it, bridge girders in the viaduct are made continuous to make them seamless. The structure is considered. That is, as shown in the side view of FIG. 5 and the plan view of FIG. 6, the own weight of the bridge girder 2 including the vehicle load is supported by the laminated rubber 33 installed at the upper end of the pier 32, and the inertial force of the pier due to the earthquake causes the bridge axial direction. The component and the component at right angles to the bridge axis are arranged between the left and right ends of the upper end of the pier 32 and the support base 34 projecting at the center of the lower surface of the main girder 2, as shown in FIG. A pair of oil dampers 6 are connected so as to open in a V shape toward the left and right ends of the. The oil damper 6 has the same structure as that shown in FIG.

In such a structure, the acceleration waveform of the sensor is integrated with the integrating amplifier 28 in the same manner as that shown in FIG.
Is amplified and integrated once to form a speed, and the output is converted into a voltage proportional to the speed by the AV converter 27. Further, after converting the voltage into a current by the servo amplifier 26, the voltage is applied to the drive coil of the flapper valve built in the servo valve 25 to drive the flapper valve and the spool valve, and the cross-sectional area of the orifice 30 is proportional to the vibration speed. And change. The initial value of the cross-sectional area of the orifice 30 and the constant of proportionality with the vibration velocity differ depending on the size of the target bridge girder, and are not specified here.

According to the second embodiment, since the characteristics of the oil damper are as shown in FIG. 4, vibration and noise at the time of passing through the viaduct joint during traveling of the vehicle are reduced, so that the bridge girder of the viaduct is reduced. It is possible to make the structure continuous and eliminate the bridge girder seams.

[0015]

In summary, according to the invention of claim 1, both ends are closed by the end plates, respectively, and the inside is symmetrically partitioned by the partition wall in the central part into the front chamber and the rear chamber, and the both ends are A cylindrical cylinder having a central hole of the same diameter penetrating on the same center line of the plate and the partition wall and having an axial orifice eccentrically penetrating the partition wall, and a central hole of the both end plates and An inner peripheral wall of each chamber is provided so as to coaxially project at the central position of the front chamber and the rear chamber of a round bar that is fluid-tightly and slidably inserted into the center hole of the partition wall, and has an outer periphery that is fluid-tight and slidable. In a cylinder type oil damper consisting of a piston rod having a front piston and a rear piston slidably contacting each other, and working oil sealed in the space between the two pistons, the central portion of the cylindrical cylinder By having a servo valve that protrudes around the circumference and increases or decreases the cross-sectional area of the orifice in proportion to the magnitude of the input signal, not only large-amplitude vibration but also small amplitude like bridges constantly vibrates in the bridge axis direction. The present invention is extremely useful industrially because a high-performance, high-damping cylinder-type oil damper that effectively suppresses vibrations even in a steel structure is being obtained.

According to the invention of claim 2, claim 1
In the servo valve, an integrating amplifier which inputs the acceleration of the object output from the acceleration detector and an AV converter which converts the amplitude of the speed signal output from the integrating amplifier into a voltage signal, By providing a servo valve input signal circuit comprising a servo amplifier for amplifying an output voltage signal of the AV converter and inputting it to the servo valve, in addition to the effect of the invention of claim 1, a small amplitude acceleration signal is provided. The present invention is extremely useful industrially because a high-damping cylinder type oil damper for damping an object is also obtained by operating against.

[Brief description of drawings]

FIG. 1 is an overall side view showing a first embodiment in which the present invention is applied to a cable-stayed bridge.

FIG. 2 is an enlarged view showing a portion II of FIG.

FIG. 3 is a longitudinal sectional view showing the high damping oil damper of FIG. 2 and a control system diagram of its orifice.

FIG. 4 is a damping characteristic diagram of the high damping type oil damper shown in FIG.

FIG. 5 is an overall side view showing a second embodiment in which the present invention is applied to a viaduct.

FIG. 6 is a plan view of FIG.

FIG. 7 is a vertical cross-sectional view showing a conventional oil damper.

FIG. 8 is a damping characteristic diagram of the oil damper of FIG. 7.

[Explanation of symbols]

 1 Main Tower 2 Main Girder 3 Cable 4 Pier 5 End Pier 6 Oil Damper 7 Pin Joint 20 Cylinder 21 Bulkhead 22 Piston 23 Piston Rod 24 Hydraulic Oil 25 Servo Valve 26 Servo Amplifier 27 AV Converter 28 Integral Amplifier 29 Accelerometer (Acceleration) Detector) 30 Orifice 32 Bridge pier 33 Laminated rubber 34 Support stand

Claims (2)

[Claims] 1. Both ends are closed by end plates, and the inside is symmetrically partitioned by a central partition into a front chamber and a rear chamber, and the both end plates and the partition are penetrated on the same center line. A cylindrical cylinder having a central hole of the same diameter and an axial orifice eccentrically penetrating the partition wall, and a fluid-tight and sliding contact with the central holes of the both end plates and the partition wall. A front piston and a rear piston, which are coaxially projecting at the central positions of the front chamber and the rear chamber of the round rod freely inserted, and whose outer circumferences are fluid-tight and slidably slidably contact the inner peripheral walls of the chambers, respectively. In a cylinder type oil damper consisting of a piston rod and a working oil sealed in the space between the two pistons, the cylinder type oil damper is projected on the outer periphery of the central portion of the cylindrical cylinder and is proportional to the magnitude of the input signal. A high damping cylinder type oil damper comprising a servo valve that increases or decreases the cross-sectional area of the orifice. 2. The integrating amplifier according to claim 1, which is placed in front of the servo valve and which inputs an acceleration of an object output by an acceleration detector, and an amplitude of a speed signal output by the integrating amplifier, which is converted into a voltage signal. A high damping cylinder type oil having a servo valve input signal circuit comprising an A-V converter and a servo amplifier for amplifying an output voltage signal of the A-V converter and inputting it to the servo valve. Damper.